Urban air pollution is rapidly increasing in Indian cities. It affects the health and mental status of urban dwellers. In the present study, air pollutants data were collected for a year 2016 at 4 locations in Delhi from Central Pollution Control Board. The present study incorporates the analysis of the ambient air in Delhi city using Air Quality Index (AQI). An AQI is proposed for the city of Delhi, India for easy data interpretation and understanding of air quality. The air pollutants analyzed are Sulfur dioxide (SO2), Nitrogen dioxide (NO2) and Particulate matter (PM2.5). The locations selected are Dwarka, R.K Puram, Panjabi Baugh, and Anand Vihar. The AQI were calculated using IND-AQI procedure. It has been observed that AQI’s values of all four locations falls under very poor category. The overall AQI was found under very poor and sever categories. It was found that AQI values were very high during winter season and low during monsoon season. The AQI of PM2.5 was found exceeding the limits for all the months in each location. Thus, it is observed that PM2.5 is critical pollutant at these four locations in Delhi.